"""Diagnostics mirrored to a file, since this device's logcat surfaces neither
Chaquopy stdout nor android_utils.log output.

The file lives under `get_files_dir()` (app external storage), so it is
readable over adb:
  adb shell cat "/sdcard/Android/data/com.exteragram.messenger/files/exteraGram/exteraGram Files/message_logger/diag.log"
"""

import os
import time
import traceback

_MAX_BYTES = 256 * 1024
_path = None


def _file():
    global _path
    if _path is None:
        try:
            from file_utils import get_files_dir

            directory = os.path.join(get_files_dir(), "message_logger")
            os.makedirs(directory, exist_ok=True)
            _path = os.path.join(directory, "diag.log")
        except Exception:
            _path = ""
    return _path


def log(message):
    line = time.strftime("%H:%M:%S ") + str(message)
    try:
        from android_utils import log as android_log

        android_log("[message_logger] " + line)
    except Exception:
        pass
    path = _file()
    if not path:
        return
    try:
        mode = "a"
        if os.path.exists(path) and os.path.getsize(path) > _MAX_BYTES:
            mode = "w"
        with open(path, mode, encoding="utf-8") as handle:
            handle.write(line + "\n")
    except Exception:
        pass


def error(where, exc=None):
    detail = traceback.format_exc() if exc is not None else ""
    log(f"ERROR {where}: {exc!r}\n{detail}")